<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>双飞翼布局</title>
  <style type="text/css">
    body{
      min-width: 550px;
    }
    .col{
      float: left;
    }
    #main{
      width: 100%;
      height: 200px;
      background-color: gray;
    }
    #main-wrap{
      margin: 0 190px 0 190px;
    }
    #left{
      width: 190px;
      height: 200px;
      background-color: plum;
      margin-left: -100%;
    }
    #right{
      width: 190px;
      height: 200px;
      background-color: seagreen;
      margin-left: -190px;
    }
  </style>
</head>
<body>
  <div id="main" class="col">
    <div id="main-wrap">this is main</div>
  </div> 
  <div id="left" class="col">this is left</div> 
  <div id="right" class="col">this is right</div> 
</body>
</html>